The invention disclosed and claimed herein relates generally to a means for controlling projected light images, and more particularly to a means for readily varying the positions and dimensions of animated colored light images projected onto visual display media.
Apparatus for visually representing the phenomenon of combustion by providing animated images of smoke and flame have been found to be quite useful for numerous training, demonstrative, and other purposes. For example, in classroom training for firefighters, an instructor may employ such means to simulate a tactical problem by selectively projecting flame and smoke images on a visual representation of a building or other environment where fire can occur, the animation of the images providing a heightened sense of realism or urgency.
While some devices are presently available for such simulations, they may employ cumbersome or awkward means of adjustment. In some such devices, for example, a glass overlaid with carbon paper is positioned between a light source and display screen, and to project an image representing combustion at a selected position on the screen, an amount of carbon paper must be scraped away from a corresponding position on the glass, allowing light to pass through to the screen. However, if a user of the device miscalculates the position on the glass, he must make adjustment by first covering the scraped area with black paint and then scrape the carbon paper from a second area. Such means of adjustment may be inhibiting in classroom training for firefighters if it is desired to make rapid variations in the displayed images of combustion in order to simulate a sudden change in the nature of a tactical problem, or to demonstrate the manner in which a fire situation responds to various acts of fire control. In addition, presently available devices may require the use of at least two separate light sources, one to project a flame image and another a smoke image, and may comprise structure which is expensive, bulky, and unadaptable for other purposes.